Darwinian Debunking Reconsidered

What can evolutionary theory tell us about morality? From descriptive claims that explain morality as an evolved trait to normative (or prescriptive) claims that rely on evolution to describe how humans ought to behave, philosophers have debated whether or not evolutionary theory can or should inform moral theory. Most recently, the debate about evolutionary ethics has shifted to metaethics. In this case, philosophers have sought after evolutionary explanations in the hopes of resolving long-standing debates between moral realists and moral antirealists. These metaethical debates have centered on what are called Darwinian debunking arguments. Proponents of the Darwinian debunking argument, such as Michael Ruse, Sharon Street, and Richard Joyce, seek to use evolutionary explanations to undermine moral realism. Opponents of Darwinian debunking arguments, such as David Enoch and Erik J. Wielenberg, attempt to defend moral realism by establishing a brand of moral realism consistent with the same evolutionary explanations that debunkers use to undermine moral realism. While those engaged in the debate generally agree that morality is an evolved trait and that evolutionary explanations can help resolve the metaethical controversy, they disagree over which metaethical position—moral realism, moral antirealism, or moral skepticism—those evolutionary explanations support. This essay provides an analysis of Darwinian debunking arguments, the debate that surrounds it and, more generally, the use of evolutionary explanations to resolve questions about the nature and justification of moral claims. The debunking debate ends in a deadlock, however, since, as I argue, evolutionary premises fail to yield any substantive metaethical conclusions. This occurs for several reasons. First, evolutionary explanations turn out to be not only inherently speculative or hypothetical, but also historical and irregular in such a way that renders them unsuitable for resolving this metaethical debate. This leads to the second problem, that of “inferential opaqueness”: the precise connection between the evolutionary explanations (the premises) and the rejection (or acceptance) of moral realism (the conclusion) at stake in the debunking literature remains unclear. The third problem rests with the theoretical assumptions—epistemological, ontological, moral and scientific—that are embedded in both sides of the debunking debate. Such assumptions are essential to how evolutionary explanations are interpreted and thus how they are meant to support various metaethical conclusions. As a result, evolutionary considerations play a far less significant role in establishing metaethical claims than these views suggest. Finally, the challenge provided by the genetic arguments utilized on either side of the debunking debate is much more limited then their adherents seem to realize. Here I draw on and develop recent work by Kevin C. Klement and Katia Vavova